Exercise C: Building operational amplifier (OA) band-pass filter for the microphone – microphone preamplifier. Test of the filter frequency response. Signal from the piezoelectric microphone consists from a constant shift from the ground about 0.9V and the alternative component in range of +/-50mV. To digitize such signal one should remove the constant component and very low frequencies (<20 Hz) from the signal by the high-pass filter. However, frequencies of most human speech harmonics lie above 100Hz, thus, we shall take the signal above this boarder. Afterwards one has to amplify it to make the output compatible with the standard audio recording equipment that has input range +/-1 V. Also, frequencies of most of harmonics in human speech lie below 10 kHz. Thus, we shall take the signal in frequency range 100 Hz - 10 kHz. We shall learn how to realize all these functions utilizing only one operational amplifier.
Datasheets: Amplifier_opa2350.pdf, Microphone_KPCM_G60H50_44DB_1184.pdf.

Correction of B & W book: Equation on p. 6 and following explanation are not correct. It should be U = L*dI/dt. For explanation see H&H p. 28. Equations on p.13 are wrong, as they don't take into account the phase shift between voltages on R and L.. The correct is Z = R+i*Omega*L, where i^2 =-1. For explanations see H&H pp. 31-32.

9.00 - 12.00: Introduction to LabVIEW (given by Alessandro): graphical programming, data acquisition, basic exercises. Loops, data format, sub vi's, saving data to files, arrays, timing.
Exercise D.
Please check out some of the videos in the "Getting
Started with LabVIEW" playlist from the LabVIEW YouTube channel: http://www.youtube.com/user/Labview?blend=7&ob=5#p/c/B968815D7BB78F9C/0/ZHNlKyYzrPE
They are an excellent introduction to some basic features of LabVIEW.

Measuring high-resistance and low-capacitance. Exercise G: Building an impedance meter for microelectrodes, testing the impedance of metallic electrodes. Knowing the impedance of electrophysiological recording electrode is important for estimation of its recording capabilities – number of cells that can be recorded or separated, sensitivity to noise and etc. However, current that one should pass through such electrode for the measurement should not be too high: cells in the vicinity of the electrode tip can be destroyed. For the extracellular recording electrode the current should not exceed 30 nA. Most of electrical activity of single cells (spikes) lie in the frequency range 300-3000 Hz. Thus, to estimate suitability of the electrode to record such activity, its impedance is usually measured at 1000 Hz. To measure the impedance of the microelectrode we shall generate 30nA sinusoidal current with the help of signal generator and current-limiting resistor. We shall estimate the impedance of the electrode by the voltage drop on it looking at the oscilloscope. Phase shift between the generator output and signal at the electrode will allow estimate resistive (active) and capacitive parts of electrode impedance separately. Preliminary measurement of voltage drop of at non-immerged in the solution (“virtual brain”) will allow to subtract the parasitic impedance of conductive wires to get precise estimate of the electrode impedance.

Electrochemistry, electrolytes, AgCl electrode. Metal electrodes goldplating. Measuring electrode impedance before and after goldplating. Electrical processes in living organisms take place in watery solutions containing salts, proteins, carbohydrates and a host of other organic and non-organic substances. These processes are dominated to a large extent by various salts. Therefore, we will need a good understanding of the properties of electrolyte solutions and of the processes associated with them. In addition, most methods to get measurements from the wet medium are carried out with electronic instruments, which must be connected somehow to the process studied. Therefore, we are interested also in the processes at the electrodes used for measurement and stimulation. Exercise H: Goldplating of the metal electrode. Measuring its impedance before and after goldplating. Fabrication of AgCl electrode by electrochemical oxidizing the silver wire in 0.5M KCl solution (forming silver chloride layer). Measuring I/V behavior of the electrode before and after oxidizing.
SIFCO Process Gold (Alkaline) Material Safety Data Sheet: MSDS-3023.pdf.

9.00 - 12.00: Real-time control. Feedback, close loop control of the microdrive in Labview. In many cases one needs not only to measure the physical parameters, but also influence on the experimental system in real time depending on results of measurements. We shall study how to achieve precise (about 1 micrometer) positioning of the microdrive for the microelectrode depending on the signal from position sensor. Exercise J: Moving microdrive to a predetermined position.

The basic LabView2010 library of I2C examples can be taken here: Basic.llb.
This library should be already preinstalled in all Windows computers in the lab. Just go to LabView menu "Help" -> "Find Examples..." Then search for "I2C".